1. Field of the Invention
This invention relates to a fluid coupling for an engine which controls the rotation speed of a cooling fan of a water-cooled engine, in particular relates a fluid coupling for an engine of a vehicle.
2. Description of the Related Art
A conventional fluid coupling for an engine is disclosed in Japanese Patent Laid Open No. 3(1991)-234931. The fluid coupling for an engine disclosed in the prior art comprises a shaft, a housing rotatably supported on the shaft, a cover fixed to the housing, a ring-shaped separation plate which separates a chamber defined by the housing and the cover into a store chamber and an operation chamber, valve means which open and close an opening disposed on the separation plate and a rotor disposed in the operation chamber and fixed on the shaft. The separation plate is formed with a first separation portion and a second separation portion which are arranged in series in the axial direction of the shaft so as to separate the store chamber into a first store chamber and a second store chamber. A diameter of an inner circumference of the first separation portion is provided to be smaller than that of the second separation portion so as to regulate a quantity of the fluid flows into the operation chamber.
However because the separation portions are arranged in series in the axial direction of the shaft so as to form the first store chamber and the second store chamber, the fluid coupling is enlarged and includes a large amount of the fluid. Further, because the separation portions can not easily mounted in the store chamber, the fluid coupling can not easily assembled.